What makes you think Sergio had/has any trade value?
Sergio would have had value, had Pritchard recogized his real talent level and traded him after his rookie year, when other teams were impressed with him. But Pritchard runs a car into the ground before trading it, because he's always unsure.
But okay, let's say Sergio had no trade value when Pritchard finally got around to doing something. If true, then Pritchard basically bought the Pendergraph pick for $3M and a #2 pick, and threw in someone with zero trade value.
Pritchard routinely buys late 1st round picks for $3M (and gets the praise instead of Paul Allen's generosity, when many owners are slobbering over that money and will cough up a pick). This time, Pritchard paid the usual $3M bribe and a #2 pick for only a 2nd round pick, Pendergraph. Why didn't he buy an earlier pick with it as usual? And if Pendergraph is so good (I've seen nothing special for a 2nd rounder), remember that we paid the same as 4 $800K Juwan Howards. Instead of wasting money on inexperience, especially 2nd round picks who will never start, why not spend it on experienced starters.
Pritchard was also obviously targeting Pendergraph who should enjoy a solid backup Big career. Complaining about that move in retrospect seems odd as Portland came out better for it.
He'll last a few years, but I wouldn't call that a solid career. Cunningham will last longer. And I didn't complain about Sergio and #38 being traded for #31. What I said was that Pritchard pays $3M to make every trade happen, even the trivial Sergio trade. So to satisfy your saying that Sergio had zero value, I have now twisted the trade to try to justify the $3M by saying that Pritchard really bought Pendergraph for $3M, and threw in Sergio. Which as I argued, still wasn't worth it. And even if it was, it doesn't negate my original point--that Pritchard lacks the talent to make trades without the crutch of Paul Allen's $3M. So that when he trades Webster, he'll get about the same as he did for Sergio.